Many forms of signal transmission are available wherein the information signal modulates a carrier signal and the signals are then transmitted. Modulation techniques include Amplitude Modulation (AM), Frequency Modulation (FM), Phase Modulation (PM), Pulse Code Modulation (PCM), etc. In Amplitude Modulation, the carrier signal waveform's amplitude is made to vary proportionately with the modulating signal. It is often desirable to transmit digital information in this manner, for example, when communicating between computers. The squared edges of the original digital signal are often lost in the modulation, transmission, and reception process due to bandwidth limitations which remove the high frequency components which make up the digital signal. What is recovered is a waveform having peak magnitudes substantially equal to the peak magnitudes of the original digital signal but with substantially reduced rise and fall times.
After receiving and removing the carrier signal waveform, it is often necessary to not only reconstruct the digital information of ones and zeros from the modulating waveform representing the original digital signal, but it is also necessary to recover the correct timing. This is accomplished with a data slicer circuit, wherein the data slicer may provide squared edges which were lost during modulation and transmission. A common problem associated with recovering the digital signal is loss of the original duty cycle and jitter which is data dependent.
Thus, what is needed is a self adjusting data detector for recovering and reconstructing a digital signal from a modulated carrier signal with the duty cycle of the original modulating signal intact and free from data dependent jitter.